This is a long-term controlled trial to evaluate the efficacy of periodic multiphasic health checkups in preventing or postponing morbidity, disability, and mortality. A group of over 5,000 middle-aged men and women have been urged to take annual multiphasic health checkups since 1964. A comparable control group has received no such urging. Follow-up of both groups for utilization of outpatient facilities, hospitalization, self-reported morbidity and disability, and mortality continues. In addition, clinical charts of all study subjects are being reviewed for a) measures of health status at the start of the project, and b) evidence of mechanisms by which increased exposure to multiphasic health checkups may affect health outcome.